* feat(shortcuts): add customizable keyboard shortcuts via GUI
Implement configurable keyboard shortcuts for toggling voice recognition,
allowing users to choose between Ctrl+Ctrl, Alt+Alt, Shift+Shift, or
Super+Super (Windows key) double-tap shortcuts.
Changes:
- Add shortcuts configuration section to settings dialog with dropdown
- Update keyboard backends (pynput and evdev) to support configurable
modifier keys for double-tap detection
- Add SUPPORTED_SHORTCUTS, SHORTCUT_DISPLAY_NAMES constants in base module
- Update KeyboardShortcutManager to accept and pass shortcut configuration
- TrayIndicator now reads shortcut from config on startup
- Add comprehensive tests for shortcut configuration and parsing
The default shortcut remains Ctrl+Ctrl for backward compatibility.
Changes take effect after app restart (noted in UI).
Closes#16
* feat(shortcuts): enable live shortcut switching without app restart
Add restart_with_shortcut() method to KeyboardShortcutManager that stops
the listener, updates the shortcut configuration, and restarts with the
new shortcut. The settings dialog now applies shortcut changes immediately
with visual feedback indicating success.
- Add restart_with_shortcut() to KeyboardShortcutManager
- Add update_shortcut() to TrayIndicator for exposing live updates
- Update SettingsDialog to use callback for immediate shortcut changes
- Show green success message when live switching succeeds
- Add 7 new tests for restart_with_shortcut functionality
* fix: use Python 3.8 compatible context manager syntax
Convert parenthesized context manager (Python 3.10+) to nested with
statements for Python 3.8 compatibility in test_keyboard_shortcuts.py
